Apparatus for cooling transformers



June 2, 1925. 1,540,536

| H. BURNHAM APPARATUS FOR COOLING TRANSFORMERS Filed April 6, 1923 //7 ventor: Locrke H Earn/7am,

M'sAttor-ney Patented June 2, 1925.

UNITED STATES PATENT OFFICE.

LOCKE H. BURNHAMiOF PITTSFIELD, MASSACHUSETTS, ASSIGNOR- TO GENERAL ELEC- TRIC COMPANY, A GORPORATIDN' OF NEW YORK.

APPARATUS FOR COOLING TRANSFORMERS.

Application filed April 6,

To all whom it may concern:

Be it known that I, LOCKE H. BUitN -IAM, a citizen of the United States, residing at Pittsfield, in the county of Berkshire, State of Massachusetts, have invented certain new and useful Improvements in Apparatus for Cooling Transformers, of which the followin is a specification.

y invention relates to apparatus for cooling transformers and more particularly to transformers which are immersed in a body of oil for cooling and insulating purposes. One of the main factors which determine the maximum load capacity of a transformer is the rise in temperature of its various parts occasioned by the load which it carries when in operation. Any means, therefore, which is effective in increasing the rate at which the heat generated by the load is dissipated will increase the load rating of the transformer or the value of the maximum load which the transformer can carry without exceeding safe temperature values. The general object of the present invention is to rovide an improved arrange ment for dissipating the heat generated in a transformer during its operation.

The rinciples of the invention will be explained in connection with the accompanylng drawing which shows an oil immersed transformer equipped with cooling means constructed in accordance with the invention, parts being broken away to reveal details.

The particular arrangement shown in the drawing includes a transformer 1 immersed in a body of cooling and insulating oil 2 held in a casing 3. A pipe 4, immersed in the oil 2 is arranged to carry a current of cool water supplied from any suitable source of supply to absorb and carry away from the oil the heat generated by the immersed transformer. This pipe 4 is shown as being formed in a helix or coil supported just inside the wall of the casing 3 so as to sur round the transformer. A cylinder 5Tpreferably of insulating material, in the space between the transformer and the pipe coil 4 serves to separate the cool oil about the pipe coil from the warm oil about the transformer. By convection, then, the oil ascends inside the cylinder 5 where it absorbs heat from the transformer and descends outside the cylinder '5 where the heat is given up to the pipe coil 4 to be carried away by the our- 1928. Serial No. 630,341.

rent of water flowing in the pipe coil. I The provision of this cylinder 5 15 not essential but is often desirable to improve the flow of 011 and the consequent transfer of heat betw ien the transformer and the cooling pipe cor.

In accordance with theinvention, means are provided for increasing the efiiciency of the pipe coil 4 in cooling the oil and also the efficlency of the oil in absorbing heat from the transformer. A plurality of small pipes 6 are supplied with cooling and insulating oil under pressure from a suitable source such as the pipe 7 leading from a pressure pump 8. The oil in the pipes 6 is forced through small openings in their lower ends 1n jets which are preferably directed downwardly and to one side along the surface of the cooling pipe coil 4:. The oil thus pumped into the casing 3 is supplied to the pump 8 from the casing through a pipe connection 9 so that the amount of oil in the casing is maintained substantially constant.

The jets of oilissuing from the pipes 6 and striking along and against the cool surfaceof the cooling coil 4 obviously increase the rate at which oil is brought into contact with'this surface and consequently the rate at which heat is transferred from the oil to the cooling coil. A further advantage of the oil jets is that the downward component of their-force increases the flow of oil and consequently the heat transfer between the transformer and the cooling coil 4. A still further advantage of the oil jets is that the side or horizontal component of their force causes the whole body of oil, or at least that portion about the cooling coil 4, to move around in the direction of the individual turns of the cooling coil. This keeps the oil moving in the restricted spaces between the turns of the cooling coil and so increases heat transfer. As indicated in the drawing, the several pipes 6 have their 0 enings through which the jets of oil are owed so disposed that the jets are well distributed ahout the surface of the cooling coil 4: so as to act efficiently on the whole body of oil about this cooling coil.

What I claim as new and desire to secure hy Letters Patent of the United States, is:

1. The combination with a casing, of a transformer immersed in oil within said casing, there being a cooled surface in contact with said oil, and means for forcing a plurality of jets of oil agamst said cooled surface. a

2. The combination with a casing, of a transformerimmersed in oil Within said casing, whereby convection currents of oil past said transformer are produced by the heat generated by the transformer during its operation, and meansdistributed about said transformer for forcing a plurality of jets of oil into the body of oil surrounding the transformer in directions to increase said convection currents.

3. The combination with a casing enclosing an oil immersed transformer, of a pipe immersed in the oil for carrying a current of cooling liquid, whereby a convection current of oil will be caused to flow downwardly past said pipe, and means for forcing a plurality of jets of oil along the surface of said pi e in directions to increase said downward ow.

4. The combination with a casing enclosing an oil immersed transformer, of a helica pipe for carr ing a current of coolin liquid, said pi e being immersed in the 01% and surrounding the transformer, and means having openings directed downwardly and sidewise for forcing a plurality of jets of oil along the surface of said pipe in downwardly and sidewise directions.

In witness whereof, I have hereunto set my hand this 4th day of April, 1923.

LOCKE H. BURNHAM. 

